Purpose:
To determine the effect of exogenous lipid supplements on the clinical, functional and biochemical aspects of tear lipid layer in habitual contact lens wearers.

Methods:
Ten participants were recruited to a randomized crossover trial which included a baseline visit with no intervention and visits after using an emulsion drop containing phosphatidylethanolamine (PE) (Systane Balance, Alcon) and a control saline drop (n=5), or a liposomal spray containing phosphatidylcholine (PC) (Tears again, BioRevive) and a saline spray as a control (n=5). Participants used the intervention/controls 3 times a day for two weeks with 24 hours washout period between the intervention and control visits. Visits occurred following 14 days of use of each intervention type or control after 8 hours of lens wear. All participants wore Ciba Vision, Air Optix® before starting each intervention. Ocular comfort scores, stability of the tear film (TBUT) and tear evaporation rate (TER) were assessed. Basal tears were collected into a glass micro-capillary tube and analyzed by mass spectrometry. Comparison and associations between the variables were analyzed using Friedman’s ANOVA and Spearman correlation coefficient respectively.

Results:
The mole % of PE in the total lipidome of those who used the emulsion drop was significantly (p=0.04) higher 0.94 ± 0.4% than those with saline drop 0.43 ± 0.3%. As the mole % of PE increased in the tear lipidome of those treated with the emulsion drop, TBUT significantly increased (R2=0.50 p=0.01) and TER significantly reduced (R2=0.20 p=0.03). There was a higher concentration of lysophosphatidylcholine (LPC) (mg/μl) in their tear lipidome when the liposomal spray was used and this resulted in an increased tear evaporation rate (R2=0.50 p=0.03) and a shorter but not statistically significantly TBUT (R2=0.10 p=0.06). The increased mole % of lysophospholipids (LPC + LPE) was associated with a decreased ocular comfort (R2=0.10 p=0.02) during lens wear

Conclusions:
Compared with placebo, the exogenous phospholipid emulsion drop significantly changed the mole ratio of PE in the tear lipidome of habitual contact lens wearers and improved their tear film stability and tear evaporation rate. Interestingly, an adverse effect of lysophospholipids on the tear evaporation rate and ocular comfort was observed. However, these observations needed to be confirmed in a larger population.